JP3292255B2 - Method for producing aqueous polyurethane dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aqueous cationic polyurethane dispersion. More particularly, it relates to a method for producing an aqueous polyurethane dispersion using a special polyol component having a tertiary and / or quaternary nitrogen atom.

[0002]

2. Description of the Related Art A typical method for producing a conventional aqueous dispersion of a cationic polyurethane includes, for example, an alkyl dialkanolamine such as N-ethyldiethanolamine;
A method is known in which another polyol is reacted with a polyisocyanate as an essential component, and the tertiary nitrogen atom is neutralized with an acid or quaternized with an alkylating agent or the like to be cationized.

[0003]

However, the above-mentioned aqueous dispersion of cationic polyurethane has a drawback that its stability over time is insufficient, and its coating is significantly colored by heat.

[0004]

The inventors of the present invention have conducted intensive studies on a method for producing a cationic polyurethane aqueous dispersion which has a good storage stability and gives a film which is not easily colored even by heat. When a polyol having a specific structure having a tertiary and / or quaternary nitrogen atom is used instead of a polyol such as N-methyldiethanolamine,
The inventors have found that the above-mentioned problems can be solved, and have completed the present invention.

That is, the present invention relates to a radically polymerizable unsaturated monomer containing a tertiary and / or quaternary nitrogen atom in the presence of a mercaptan-based chain transfer agent having two or more hydroxyl groups and one mercapto group. Macromonomer (A) obtained by subjecting a polymer to radical polymerization, and polyisocyanate (B)
And a method for producing an aqueous polyurethane dispersion, characterized by reacting the same as an essential component.

(Constitution) The mercaptan-based chain transfer agent having two or more hydroxyl groups and one mercapto group used in the present invention (hereinafter, simply referred to as a chain transfer agent) is as follows.
For example, 1-mercapto-1,1-methanediol, 1
-Mercapto-1,1-ethanediol, 3-mercapto-1,2-propanediol, 2-mercapto-1,
2-propanediol, 2-mercapto-2-methyl-
1,3-propanediol, 2-mercapto-2-ethyl-1,3-propanediol, 1-mercapto-2,
2-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol, 2-mercaptoethyl-2-ethyl-1,3-propanediol, and the like.

The radically polymerizable unsaturated monomer containing a tertiary and / or quaternary nitrogen atom used in the present invention includes, for example, dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) Acrylate,
Dimethylaminopropyl (meth) acrylate, diethylaminomethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dimethylallylamine, dimethyldiallylammonium chloride, acryloylpyrrolidine and these monomers and hydrochloric acid, sulfuric acid, Inorganic acids such as nitric acid; organic acids such as formic acid, acetic acid, and propionic acid; methyl chloride, methyl bromide, dimethyl sulfate, diethyl sulfate, benzyl chloride, p-nitrobenzyl chloride, benzyl bromide, ethylene chlorohydrin, ethylene bromide Examples include quaternary nitrogen atom-containing monomers that have been reacted with a quaternizing agent such as hydrin, epichlorohydrin, and brombutane.
These monomers are used alone or in combination.

In some cases, it is possible to copolymerize with the following monomers. Examples of them are
Methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, and other alkyl (meth) acrylates, acrylonitrile, methacrylonitrile, styrene, vinyl acetate, glycidyl (meth) acrylate, aryl glycidyl Glycidyl group-containing monomers such as ethers, methacryloyloxyethyl acid phosphate, methacryloyloxypropyl acid phosphate and phosphoric acid group-containing monomers such as esters or salts thereof,
Sulfonic acid group-containing monomers such as styrene sulfonic acid and salts thereof, amide group-containing monomers such as (meth) acrylamide, perfluorooctylethyl (meth) acrylate, N-methyl (propyl) perfluorooctyl sulfone Perfluoroalkyl group-containing monomers such as amidoethyl (meth) acrylate; polysiloxane group-containing monomers such as polydimethylsiloxylpropyl methacrylate; methoxypolyethylene glycol (meth)
Examples include polyoxyethylene group-containing monomers such as acrylates.

As a method for producing the tertiary and / or quaternary nitrogen atom-containing macromonomer of the present invention, a conventionally known method can be applied. For example, in the presence of the chain transfer agent,
Radical polymerization of the radically polymerizable unsaturated monomer containing the tertiary and / or quaternary nitrogen atom-containing radically polymerizable unsaturated monomer as an essential component, using a polymerization catalyst if necessary It is easily obtained.

Examples of such polymerization catalysts include acyl peroxides such as benzoyl peroxide, tertiary butyl hydroperoxides, alkyl hydroperoxides such as p-methane hydroperoxide, and di-tertiary butyl peroxides. Examples include peroxide compounds such as dialkyl peroxides, and azobisisobutyronitrile compounds.

The amount of the tertiary and / or quaternary nitrogen atom-containing macromonomer (A) used for obtaining the aqueous polyurethane dispersion of the present invention is sufficient to obtain a stable aqueous dispersion. And more specifically, the solid content of polyurethane resin 1
The content of tertiary and / or quaternary nitrogen atoms per 100 parts by weight is at least 0.01 equivalent or more, preferably 0.0
It needs to be 2 to 0.2 equivalents.

The polyisocyanate (B) used in the present invention includes, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane Diisocyanate,
2,4′-diphenylmethane diisocyanate, 2,
2'-diphenylmethane diisocyanate, 3,3'-
Dimethyl-4,4'-biphenylenediisocyanate,
3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate,
4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,
4'-dicyclohexylmethane diisocyanate, 3,
3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate and the like.

The other active hydrogen-containing compounds which can react with isocyanate groups used in the production of the aqueous polyurethane dispersion of the present invention are, for convenience, an average molecular weight of 300-1.
It is classified into a high molecular weight compound having a molecular weight of preferably 5,000 to 5,000, and a low molecular weight compound having a molecular weight of 300 or less.

Examples of the high molecular weight compound include polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols,
Polyacrylate polyol, polyesteramide polyol, polythioether polyol and the like can be mentioned.

As the polyester polyol, for example, ethylene glycol, propylene glycol, 1,3-
Propanediol, 1,4-butanediol, 1,5-
Pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight 300 to 6,000), dipropylene glycol, Tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,
4-cyclohexanedimethanol, bisphenol A,
Glycol components such as hydrogenated bisphenol A, hydroquinone and their alkylene oxide adducts and succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-
Cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
Naphthalic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid and anhydride or ester-forming derivatives of these dicarboxylic acids; p-hydroxybenzoic acid, p- (2-hydroxyethoxy) ) Polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, in addition to polyesters obtained by a dehydration condensation reaction with an acid component such as benzoic acid and ester-forming derivatives of these hydroxycarboxylic acids; Is a copolymerized polyester.

Examples of the polyether include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, Glycerin, trimethylolethane, trimethylolpropane, sorbitol, sucrose, aconit sugar, trimellitic acid, hemicellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, 1,2,2 One or more compounds having at least two active hydrogen atoms, such as 3-propanetrithiol, are used as initiators for ethylene oxide, propylene oxide, Emissions oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene, include those addition polymerization in a conventional manner one or more monomers and the like.

Examples of the polycarbonate polyol include compounds obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol and the like with diphenyl carbonate and phosgene.

The low molecular weight compound includes a compound having a molecular weight of 30.
A compound containing at least two active hydrogens in the molecule of 0 or less, for example, a glycol component used as a raw material of a polyester polyol; a polyhydroxy compound such as glycerin, trimethylolethane, trimethylolpropane, sorbitol, and pentaerythritol; Ethylenediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, 3,
3′-dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, 1,2-propanediamine, hydrazine, diethylenetriamine,
Examples include amine compounds such as triethylenetetramine.

The method for producing the aqueous polyurethane dispersion of the present invention may be any of the conventionally well-known methods, for example, the following method.

If necessary, a neutralizing agent may be added to the organic solvent solution or organic solvent dispersion of the polyurethane resin obtained by reacting the macromonomer (A) and other active hydrogen-containing compounds with the polyisocyanate (B). To obtain an aqueous dispersion by mixing aqueous solutions containing the same.

The urethane prepolymer having a terminal isocyanate group obtained by reacting the macromonomer (A) and other active hydrogen-containing compounds with the polyisocyanate (B) is mixed with an aqueous solution containing a neutralizing agent, if necessary. Or a method of adding a neutralizing agent to a prepolymer in advance, mixing water, dispersing the mixture in water, and reacting with a polyamine to obtain an aqueous dispersion.

An aqueous solution containing a polyamine and, if necessary, a neutralizing agent is added to a urethane prepolymer having a terminal isocyanate group obtained by reacting the macromonomer (A) and other active hydrogen-containing compounds with the polyisocyanate (B). Or a neutralizing agent is added in advance to the prepolymer, if necessary, and then mixed with an aqueous solution containing a polyamine to obtain an aqueous dispersion.

The polyurethane resin and urethane prepolymer containing terminal isocyanate groups according to the present invention are produced by a conventionally known method. For example, the polyisocyanate and the active hydrogen-containing compound (including the macromonomer (A))
In the case of a polyurethane resin, the equivalent ratio of an isocyanate group to an active hydrogen group is 0.8: 1 to 1.2: 1, preferably 0.9: 1 to 1.1: 1. In the case of a group-containing urethane prepolymer,
The reaction is carried out at a ratio of 1.1: 1 to 3: 1, preferably 1.2: 1 to 2: 1 at 20 to 120C, preferably 30 to 100C.

These reactions can be carried out in the absence of a solvent, but an organic solvent can also be used for the purpose of controlling the reaction of the reaction system or reducing the viscosity. Examples of the organic solvent include, but are not limited to, aromatic hydrocarbons such as toluene and xylene; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; acetates such as ethyl acetate and butyl acetate; dimethylformamide; Amides such as -methylpyrrolidone.

When such an organic solvent is removed by distillation from the polyurethane resin aqueous dispersion finally obtained, it is preferable to use a solvent having a relatively low boiling point which is easily removed by distillation. Even when an organic solvent having a boiling point of 100 ° C. or higher must be used, the amount of use is preferably kept to a minimum.

In the above methods (1) to (4), in addition to the macromonomer (A) of the present invention, a hydrophilic atomic group used in a conventional method for producing an aqueous polyurethane dispersion or an atomic group which can be made hydrophilic by neutralization is used. An active hydrogen-containing compound capable of reacting with an isocyanate group may be used in combination.

Examples of such compounds include 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfoisophthalic acid, sulfanilic acid, 1,3-phenylenediamine-4,6-
Sulfonic acid-containing compounds such as disulfonic acid and 2,4-diaminotoluene-5-sulfonic acid and derivatives thereof or polyester polyols obtained by copolymerizing them;
Carboxylic acid-containing compounds such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dioxymaleic acid, 2,6-dioxybenzoic acid, and 3,4-diaminobenzoic acid And their derivatives or polyester polyols obtained by copolymerizing them; methyldiethanolamine, ethyldiethanolamine, propyldiethanolamine, butyldiethanolamine, oleyldiethanolamine, N, N-dioxyethylaniline, N, N-dioxyethyltoluidine, alkyl 3 such as diisopropanolamine, allyldiisopropanolamine, dioxyethylpiperazine, etc.
Tertiary amino group-containing compounds and derivatives thereof or polyester polyols or polyether polyols obtained by copolymerizing them; tertiary amino group-containing compounds and derivatives thereof or polyester polyols or polyethers obtained by copolymerizing them Polyol, methyl chloride, methyl bromide, dimethyl sulfate, diethyl sulfate,
A reaction product of a quaternizing agent such as benzyl chloride, p-nitrobenzyl chloride, benzyl bromide, ethylene chlorohydrin, ethylene bromohydrin, epichlorohydrin, or bromobutane; a polymer containing at least 30% by weight of ethylene oxide repeating units Having a molecular weight of 300 to 10,000 containing at least one active hydrogen therein
Nonoxy group-containing compounds such as polyoxyethylene-polyoxyalkylene copolymer or a polyester polyether polyol obtained by copolymerizing these, and
These may be used alone or in combination.

In the method of the present invention, if necessary, an emulsifier may be used in combination. Examples of such emulsifiers include nonionic emulsifiers such as polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene sorbitol tetraoleate; fatty acid salts such as sodium oleate; Anionic emulsifiers such as ester salts, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, sodium alkanesulfonates, sodium alkyldiphenyl ether sulfonates; polyoxyethylene alkyl sulfates, polyoxyethylene alkylphenyl sulfates Nonionic anionic emulsifiers such as salts are exemplified.

The neutralizing agent for neutralizing the tertiary and / or quaternary nitrogen atoms which can be used in the production of the aqueous polyurethane dispersion of the present invention includes, for example, inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid. Organic acids such as formic acid, acetic acid, and propionic acid; methyl chloride, methyl bromide, dimethyl sulfate, diethyl sulfate, benzyl chloride, p-nitrobenzyl chloride, benzyl bromide, ethylene chlorohydrin, ethylene bromhydrin, epichlorohydrin And a quaternizing agent such as brombutane. The neutralization may be performed before, during, or after the polymerization of the tertiary nitrogen atom-containing unsaturated monomer, or during or after the urethanization reaction. .

Examples of the polyamine that can be used in the production of the aqueous polyurethane dispersion of the present invention include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2-methylpiperazine, and 2,5- Dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, 3,
3′-dimethyl-4,4′-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, aminoethylethanolamine, aminopropylethanolamine, aminohexylethanolamine, aminoethylpropanolamine,
Diamines such as aminopropylpropanolamine and aminohexylpropanolamine; polyamines such as diethylenetriamine, dipropylenetriamine and triethylenetetramine; hydrazines; acid hydrazides, and these are used alone or in combination.

The aqueous polyurethane resin dispersion thus obtained may be used as it is, or may be used as an aqueous polyurethane resin dispersion by removing an organic solvent by distillation, if necessary.

Various distillation apparatuses can be used for removing the organic solvent by distillation. However, a distillation apparatus which does not release the organic solvent removed by distillation or the distillation efficiency to the atmosphere is preferable, and a thin film evaporation apparatus is particularly preferable.

In the above methods for producing an aqueous dispersion of the present invention, if necessary, in addition to water, other aqueous dispersions or aqueous dispersions, for example, vinyl acetate, ethylene acetate,
Emulsions such as acrylics and acrylic styrenes; latexes such as styrene-butadiene, acrylonitrile-butadiene, and acryl-butadiene; ionomers such as polyethylene and polyolefins; and various aqueous solutions such as polyurethane, polyester, polyamide, and epoxy resins A dispersion and an aqueous dispersion may be used in combination.

The aqueous polyurethane resin dispersion thus obtained by removing the organic solvent is a substantially solvent-free aqueous dispersion having a solid content of about 10 to 60% by weight, preferably 15 to 50% by weight. However, even when an organic solvent having a boiling point of 100 ° C. or more must be used for the production of an aqueous polyurethane resin dispersion, the amount of such an organic solvent is stopped up to 20% by weight based on the total weight of the aqueous dispersion. Should.

The aqueous dispersion of the synthetic resin obtained by the method of the present invention may be used alone or in the form of another aqueous dispersion, for example, an emulsion of vinyl acetate, ethylene vinyl acetate, acrylic, acrylic styrene or the like; Latexes such as butadiene, acrylonitrile-butadiene, and acryl-butadiene; ionomers such as polyethylene and polyolefin; polyurethane, polyester, polyamide, and epoxy-based aqueous dispersions can be blended and used in an arbitrary ratio. .

Further, fillers such as carbon black, clay, talc and aluminum hydroxide; additives such as silica sol, alumina sol, plasticizer and pigment; and film-forming aids such as alkylene glycol derivatives or dialkyl esters of aliphatic dicarboxylic acids. Emulsifiers such as fluorine or dialkyl sulfosuccinates, various leveling agents such as acetylene glycol derivatives; mineral oils, amides,
Various antifoaming agents such as silicones or a small amount of alcohols such as ethanol and isopropyl alcohol can be blended.

For the purpose of improving the durability of the aqueous dispersion, such as light resistance, heat resistance, water resistance, solvent resistance, and heat resistance, stabilizers such as antioxidants, ultraviolet absorbers, and hydrolysis inhibitors. During or after the production process of the aqueous polyurethane dispersion, or epoxy resin, melamine resin,
A crosslinking agent such as an isocyanate compound, an aziridine compound, and a polycarbodiimide compound may be blended and used.

The tertiary and / or tertiary compounds obtained by the method of the present invention
Alternatively, the quaternary nitrogen atom-containing macromonomer not only has a reaction promoting effect in the urethanization reaction, but also can be stably introduced without problems such as gelation, and the tertiary and tertiary compounds can be incorporated into the polyurethane resin. And / or introduction of a quaternary nitrogen atom is easy.

The aqueous polyurethane dispersion of the present invention thus obtained has good film-forming properties, can form a transparent and uniform film, and has good adhesion to various substrates, water resistance, Excellent in solvent resistance etc., polyester, nylon,
Various plastics such as PVC, metal, glass, paper, textile,
It is useful as an adhesive, a binder, a sizing agent, a paint, a surface treatment agent, a coating agent, a water-based gravure ink, and the like for substrates such as leather and wood.

[0040]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. In the present invention, parts and percentages are by weight unless otherwise specified.

Production Example 1 4 equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube
In a one-necked flask, 172 parts of methyl ethyl ketone, 200 parts of dimethylaminoethyl methacrylate, 10 parts of thioglycerin, and 1 part of the catalyst were charged and polymerized at 80 ° C. for 8 hours.
Hydroxyl value 26.7, amine value 187.1, solid content concentration 5
5% of a tertiary nitrogen-containing macromonomer A was obtained.

Example 1 Polycaprolactone diol having a molecular weight of 1,000 1097.
2 parts, tertiary nitrogen-containing macromonomer A 288.4 parts,
144 parts of neopentyl glycol, Dismodular W
[Hydrogenated diphenylmethane diisocyanate manufactured by Sumitomo Bayer Co., Ltd.] 524 parts, dibutyltin dilaurate 0.
4 parts and 1445 parts of methyl ethyl ketone were mixed and the mixture was heated to 75 ° C.
Reaction for 20 hours to urethanize, then glacial acetic acid 5
8 parts were added to neutralize the tertiary nitrogen atoms in the polyurethane, 4490 parts of water was gradually added dropwise with stirring to emulsify, and methyl ethyl ketone was distilled off under reduced pressure to obtain a polyurethane aqueous solution having a solid content of 30%. A dispersion was obtained. This aqueous polyurethane dispersion was extremely stable even after standing for 3 months. The film obtained from this aqueous dispersion did not discolor even when heated in a drier.

Comparative Example 1 Instead of the macromonomer A of Example 1, N-methyldiethanolamine was replaced with a macromonomer A having a tertiary nitrogen content.
In the same manner as in Example 1 except for using the same amount as
An aqueous cationic polyurethane dispersion was synthesized. Specifically, the following operation was performed.

1242 parts of polycaprolactone diol having a molecular weight of 1,000, N-methyldiethanolamine
4 parts, 43.2 parts of neopentyl glycol, 524 parts of Dismodur W, 0.4 part of dibutyltin dilaurate
And 1574 parts of methyl ethyl ketone were mixed and reacted at 75 ° C. for 20 hours to urethanate, and then glacial acetic acid 58
To neutralize the tertiary nitrogen atom derived from N-methyldiethanolamine in the molecule, and then tried to emulsify by gradually dropping 4490 parts of water under stirring, but a stable aqueous dispersion was not obtained. Was.

Example 2 Instead of neutralizing the methyl ethyl ketone solution of the polyurethane resin obtained in Example 1 with glacial acetic acid, quaternized by adding methyl iodide, then emulsifying by adding water dropwise, Further, methyl ethyl ketone was removed by distillation under reduced pressure, and the solid content was 30%.
A cationic polyurethane aqueous dispersion was obtained. This aqueous polyurethane dispersion was extremely stable even after standing for 3 months. The film obtained from this aqueous dispersion did not discolor even when heated in a drier.

Example 3 Polytetramethylene glycol having a molecular weight of 1,000 939.
6 parts, tertiary nitrogen-containing macromonomer A 709.2 parts,
866 parts of isophorone diisocyanate, 170 parts of 1,4-butanediol, and 1260 parts of methyl ethyl ketone are mixed and reacted at 70 ° C. for 6 hours to synthesize an isocyanate group-terminated prepolymer.
Of the tertiary nitrogen atom in the prepolymer was quaternized by adding 8000 parts of water while stirring at high speed with a homomixer to prepare an aqueous dispersion of the prepolymer, and 70 parts of anhydrous piperazine were further dissolved. 350 parts of an aqueous solution was added dropwise over about 1 minute, and then methyl ethyl ketone was distilled off under reduced pressure to obtain a polyurethane aqueous dispersion having a solid content of 25%. This aqueous polyurethane dispersion was extremely stable even after standing for 3 months. The film obtained from this aqueous dispersion did not discolor even when heated in a drier.

Example 4 Polyester diol having a molecular weight of 2,000 (neopentyl glycol / 1,6-hexanediol / adipic acid) 8
62.8 parts, tertiary nitrogen-containing macromonomer A370.
8 parts, 1,3 butanediol 133.2 parts, tolylene diisocyanate 348 parts, methyl ethyl ketone 865
The mixture was mixed and reacted at 75 ° C. for 12 hours to urethanize, and then 74.2 parts of glacial acetic acid was added to neutralize the tertiary nitrogen atoms in the polyurethane, and 3620 parts of water were gradually added dropwise with stirring. Then, methyl ethyl ketone was distilled off under reduced pressure to obtain a cationic polyurethane aqueous dispersion having a solid content of 30%. This aqueous polyurethane dispersion is 3
It was extremely stable after standing for a month. The film obtained from this aqueous dispersion did not discolor even when heated in a drier.

The aqueous polyurethane dispersions obtained by the production methods of the examples of the present invention were all excellent in dispersibility of various fillers.

[0049]

According to the method of the present invention, the third group as a hydrophilic group
Since a quaternary and / or quaternary nitrogen atom can be introduced into the graft chain at any molecular weight, localization of a hydrophilic group is possible,
An aqueous polyurethane dispersion having good dispersibility in water can be easily obtained even with a smaller hydrophilic group content than the conventional method. The aqueous dispersion obtained at the same time has very good stability over time and mechanical stability.

Further, since the hydrophilic group is on the side chain, various inorganic and
Good dispersibility of organic pigments or various fillers,
Further, there is an advantage that the main chain of the polyurethane resin is relatively resistant to degradation due to hydrolysis, has excellent hydrolysis resistance, and is less likely to be colored by heat.

Claims (1)

(57) [Claims] 1. A radically polymerizable unsaturated monomer containing a tertiary and / or quaternary nitrogen atom in the presence of a mercaptan-based chain transfer agent having two or more hydroxyl groups and one mercapto group. A process for producing an aqueous polyurethane dispersion, comprising reacting a macromonomer (A) obtained by polymerization and a polyisocyanate (B) as essential components.